JP2018128084A - Planet type transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planet type transmission device that can lubricate respective parts in a gear case by diffusing reserved lubricating oil in the gear case to a circumference by making good use of a counterweight coupled to a first power transmission shaft to balance with rotational unbalance of an eccentric rotary body including an eccentric shaft and a planetary gear, and further has small agitation resistance of the reserved lubricating oil.SOLUTION: A counterweight 15 has an arm part 16 extending radially from a power transmission shaft, and a weight part 17 protruding to by a tip part of the arm part 16, and is provided with a recessed part 21 at an inner peripheral surface intermediate part of the weight part 17. An amount of reserved lubricating oil Fa in a gear case 1 is so set that when a rotation-directional heat end part of the weight part 17 reaches a bottom part, the head end part is dipped in the reserved lubricating oil Fa, and when the planetary gear 10 reaches a top part, the whole planetary gear 10 is exposed above the reserved lubricating oil Fa.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a planetary transmission device used for a speed reducer and a speed increaser.

  Conventionally, as a planetary transmission device, as disclosed in Patent Document 1 below, the gear case is supported rotatably via a first bearing and a second bearing that are axially spaced apart from each other. A first transmission shaft and a second transmission shaft, an eccentric shaft coupled to the first transmission shaft, and eccentrically rotated around an axis of the first transmission shaft as the first transmission shaft rotates. A planetary gear rotatably supported by a shaft, a ring gear fixed to the gear case coaxially with the first transmission shaft and meshing with the planetary gear, and power transmission between the planetary gear and the second transmission shaft. A motion converting mechanism to perform and an oil diffusing member attached to the second transmission shaft, and by rotating the oil diffusing member, the lubricating oil stored in the gear case is diffused around to lubricate each part. Know It has been.

Japanese Patent No. 4975274

  The conventional planetary transmission device requires a dedicated oil diffusion member driven by the second transmission shaft, and the oil diffusion member is provided with a large number of oil lifting blades, and the lower part of the planetary gear is always installed. Because it is immersed in the stored lubricating oil, the stir resistance of the stored lubricating oil by the oil scraping blades and the planetary gears is large, resulting in a large power loss.

  The present invention has been made in view of such circumstances, and uses a counterweight coupled to the first transmission shaft to balance the rotational unbalance of the eccentric rotating body including the eccentric shaft and the planetary gear. It is an object of the present invention to provide a planetary transmission device in which the stored lubricating oil is diffused to the periphery so that each part in the gear case can be effectively lubricated and the agitation resistance of the stored lubricating oil is low.

  In order to achieve the above object, according to the present invention, a gear case, a first transmission shaft that is rotatably supported via a first bearing and a second bearing that are axially spaced apart from each other in the gear case, A second transmission shaft, an eccentric shaft coupled to the first transmission shaft, rotating eccentrically around the axis of the first transmission shaft as the first transmission shaft rotates, and rotatably supported by the eccentric shaft; A planet gear, a ring gear fixed to the gear case coaxially with the first transmission shaft and meshing with the planet gear, a motion conversion mechanism for transmitting power between the planet gear and the second transmission shaft, A planetary transmission device including a counterweight coupled to the first transmission shaft to suppress rotational unbalance of an eccentric rotating body including an eccentric shaft and the planetary gear, wherein the counterweight includes the first transmission shaft; An arm portion extending in a radial direction from the shaft and a weight portion projecting to the side of the distal end portion of the arm portion, and a recess is provided in an intermediate portion of the inner peripheral surface of the weight portion. A predetermined amount of lubricating oil is stored, and when the leading end of the weight portion in the rotational direction reaches the bottom, the leading end sinks into the lubricating oil and the planetary gear is at the maximum. The first feature is that the entire planetary gear is set to be exposed above the lubricating oil when reaching the upper part.

  The first transmission shaft and the second transmission shaft correspond to an input shaft 5 and an output shaft 6 in an embodiment of the present invention described later, and the first and second bearings are second and third ball bearings. The motion conversion mechanism corresponds to the second reduction gear train 9 and corresponds to B2 and B3.

  Further, in the present invention, in addition to the first feature, the weight portion is disposed between the tooth portions of the planetary gear and the ring gear that are not meshed with each other, and the weight portion is moved from the head end portion toward the recess. A second feature is that it has a concave curved surface that approaches the tooth portion of the planetary gear.

  Further, according to the present invention, in addition to the second feature, the recess is provided in a central portion of the inner peripheral surface of the weight portion, and the weight portion is configured so that the planetary gear is in accordance with the direction from both circumferential ends toward the recess. A third feature is that it has a pair of concave curved surfaces that approach the tooth portion.

  Furthermore, in the present invention, in addition to the first or second feature, a fourth feature is that the arm portion is provided with a through hole that penetrates both side surfaces of the arm portion and communicates with the recess. .

  According to the first feature of the present invention, the counterweight rotates together with the first transmission shaft so as to suppress the rotational unbalance of the eccentric rotating body including the eccentric shaft and the planetary gear. While the counterweight is rotating, while the leading end of the weight portion passes through the stored lubricating oil in the gear case, the lubricating oil is scooped up by the inner peripheral surface of the weight portion, Is guided into the recess. Since the lubricating oil is swung around from the concave portion, the weight portion diffuses to the periphery while rotating above the stored lubricating oil, and each portion in the gear case can be lubricated. Further, the oil that has flowed out from the inner peripheral surface of the weight portion and the side of the concave portion is sprinkled on the motion conversion mechanism and can be lubricated. Thus, since the counterweight also serves as the oil diffusing member, it can contribute to the simplification of the structure of the transmission device.

  In addition, there is little stirring of the stored lubricating oil in the gear case by the counterweight, and when the planetary gear reaches the uppermost position, the entire planetary gear is exposed above the stored lubricating oil. The agitation resistance of the lubricating oil is small and power loss can be kept small.

  According to the second feature of the present invention, during the rotation of the counterweight, the stored lubricating oil is smoothly sprinkled by the concave curved surface that is close to the outer periphery of the planetary gear as it goes from the leading end of the weight portion to the concave portion. ， Can be sprinkled on the planetary gear teeth. In particular, since the counterweight rotation direction and the planetary gear rotation direction are opposite, the concave curved surface can be effectively sprinkled with the lubricating oil while passing the toothed portion of the planetary gear. Therefore, the tooth portion of the planetary gear sufficiently wet with the lubricating oil meshes with the tooth portion of the ring gear, and the meshing portion can be effectively lubricated.

  According to the third feature of the present invention, in a transmission device in which the input shaft rotates forward and backward, even if the rotation direction of the counterweight changes, one of the pair of concave curved surfaces of the weight portion is not attached to the gear case. The stored lubricating oil can be sprinkled up and sprinkled on the planetary gear teeth, the meshing part of the planetary gear and ring gear can be lubricated, and the recess between both concave curved surfaces was received from either concave curved surface Each part can be lubricated by shaking and diffusing oil.

  According to the fourth feature of the present invention, the oil scooped up by the weight portion of the counterweight and guided to the concave portion passes through the through hole of the arm portion and scatters around the arm portion. It is possible to effectively lubricate the first bearing located on the opposite side to the protruding direction of the weight part.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal front view of a planetary transmission device according to a first embodiment of the invention. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. FIG. 3 is an explanatory diagram of the operation of the counterweight corresponding to FIG. 2. FIG. 4 is a sectional view taken along line 4-4 of FIG. The perspective view of the coupling body of an input shaft, an eccentric shaft, and a counterweight. FIG. 6 is a sectional view taken along line 6-6 in FIG. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. The perspective view of the coupling body of the input shaft, eccentric shaft, and counterweight which concerns on Example 2 of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  A first embodiment in which the planetary transmission device of the present invention is applied to a planetary reduction gear will be described.

  First, we will start with an explanation of the transmission system in this planetary reduction gear.

  In FIG. 1, a gear case 1 of a planetary reduction gear R is composed of first and second case halves 1a and 1b which are connected to each other by a plurality of bolts 2 with their open end faces abutted against each other. First and second bearing bosses 3 and 4 are integrally formed on the side walls of the two case halves 1a and 1b, respectively. Each of the first and second bearing bosses 3 and 4 has a cylindrical shape, and both end portions of the first and second bearing bosses 3 and 4 protrude into and out of the side walls of the corresponding first and second case halves 1a and 1b. The first and second bearing bosses 3 and 4 are arranged to be aligned on the main axis X1.

  The input shaft 5 is rotatably supported at both ends of the first bearing boss 3 via the first and second ball bearings B1 and B2, and the input shaft 5 is adjacent to the inner surface of the first ball bearing B1. A first oil seal S <b> 1 that is in close contact with the outer peripheral surface is attached to the first bearing boss 3. The output shaft 6 is rotatably supported at both ends of the second bearing boss 4 via third and fourth ball bearings B3 and B4, and adjacent to the inner surface of the fourth ball bearing B4. A second oil seal S2 that is in close contact with the outer peripheral surface of the second bearing boss 4 is mounted. Thus, the input shaft 5 and the output shaft 6 are arranged on the main axis X1. That is, the input shaft 5 and the output shaft 6 share the main axis X1.

  In the input shaft 5, an eccentric shaft 7 is integrally connected to an inner end portion facing the inner side of the gear case 1 from the second ball bearing B 2. The eccentric shaft 7 has its axis, that is, the eccentric axis X 2 is the main shaft. It occupies a position offset by a predetermined distance e in the radial direction from the line X1, and one side wall faces the inner side surface of the second ball bearing B2.

  Between the input shaft 5 and the output shaft 6, first and second reduction gear trains 8 and 9 are interposed. The first reduction gear train 8 (see FIGS. 1 and 2) includes a first planetary gear 10 and a first ring gear 11 that mesh with each other. The first planetary gear 10 is supported on the eccentric shaft 7 via the fifth and sixth ball bearings B5 and B6 arranged at intervals in the axial direction so as to be rotatable and immovable in the axial direction. Is sandwiched and fixed between the first and second case halves 1a and 1b so as to serve as part of the constituent members of the gear case 1, and is centered on the main axis X1.

  The second reduction gear train 9 (see FIGS. 1 and 4) includes a second planetary gear 13 and a second ring gear 14 that mesh with each other. The second planetary gear 13 is coaxially adjacent to the first planetary gear 10 and is supported on the eccentric shaft 7 through the fifth and sixth ball bearings B5 and B6 together with the first planetary gear 10. . Further, the second ring gear 14 is disposed concentrically with the output shaft 6, that is, on the main shaft X <b> 1 by being fitted and fixed to the outer peripheral surface of the flange 6 a provided integrally with the inner end of the output shaft 6. Both the second planetary gear 13 and the second ring gear 14 have a smaller diameter than the first planetary gear. For fitting and fixing the second ring gear 14 to the flange 6a, press fitting, caulking, welding or the like is used.

  The operation of this transmission system will be described.

For example, when rotational power is input to the input shaft 5 from an electric motor (not shown), the eccentric shaft 7 revolves around the main axis X1 as the input shaft 5 rotates. Accordingly, the rotation of the input shaft 5 is transmitted to the first planetary gear 10 as a decelerated rotation around the eccentric shaft 7 by rolling the inner periphery of the first planetary gear 10 while meshing with the stationary first ring gear 11. The reduction ratio λ1 between the input shaft 5 and the first planetary gear 10 at this time can be expressed by the following equation.
λ1 = Z1 / (Z1-Z2)

However, Z1... Number of teeth of first planetary gear 10 Z2... Number of teeth of first ring gear 11 Z1 <Z2

When the first planetary gear 10 rotates, the second planetary gear 13 integrated with the first planetary gear 10 also rotates around the eccentric shaft 7 at the same time, so that the output shaft 6 is driven to decelerate via the second ring gear 14. The The reduction ratio λ2 between the second planetary gear 13 and the second ring gear 14 at this time can be expressed by the following equation.
λ2 = Z4 (Z1−Z2) / (Z1 × Z4−Z2 × Z3)

However, Z3: Number of teeth of the second planetary gear 13 Z4: Number of teeth of the second ring gear 14 Z3 <Z4

Therefore, the overall reduction ratio λ between the input shaft 5 and the output shaft 6 can be expressed by the following equation.
λ = λ1 × λ2 = Z1 × Z4 / (Z1 × Z4-Z2 × Z3)

  As described above, the rotational power input to the input shaft 5 is supplied to the first reduction gear train 8 including the first planetary gear 10 and the first ring gear 11, and the second reduction gear including the second planetary gear 13 and the second ring gear 14. Since the gear train 9 is decelerated in two steps and transmitted to the output shaft 6, a large reduction ratio can be obtained, and a large load, for example, an axle of a vehicle (not shown) can be driven. Capacitance and miniaturization are possible.

  During this transmission, the revolution of the first planetary gear 10 around the main axis X 1 and the rotation around the eccentric axis X 2, that is, the planetary movement, is converted into a simple rotational movement by the second reduction gear train 9 and transmitted to the output shaft 6. Therefore, no precession occurs on the output shaft 6.

  The first and second planetary gears 10 and 13 rotate in the direction opposite to the rotation direction A of the input shaft 5, while the output shaft 6 rotates in the direction opposite to the rotation direction of the first and second planetary gears 10 and 13. As a result, the input shaft 5 and the output shaft 6 are rotated in the same direction A.

  Here, the first and second planetary gears 10 and 13 will be described in detail.

  The second planetary gear 13 integrally has a long axis boss portion 13a supported by the fifth and sixth ball bearings B5 and B6. One end portion of the long axis boss portion 13a greatly protrudes from the rim portion of the second planetary gear 13 and surrounds the fifth ball bearing B5, and the short axis boss portion of the first planetary gear 10 is formed on the outer periphery of the one end portion. 10a is fitted and fixed. For the fixing, press fitting, caulking, welding or the like is used.

  The first and second planetary gears 10 and 13 may be integrally molded. However, the first and second planetary gears 10 and 13 can be integrally formed by combining the individually molded ones as described above. A tooth part can be processed easily.

  The first planetary gear 10 includes a rim having a short shaft boss portion 10a, a web portion 10b extending in a radial direction from the outer periphery of the short shaft boss portion 10a, and a rim having a tooth portion on the outer periphery. The rim portion 10c is at least one end of the rim portion 10c opposite to the second planetary gear 13 and is a protruding end protruding from the side surface of the web portion 10b. Thereby, the width | variety of the rim | limb part 10c of the 1st planetary gear 10, ie, a tooth | gear width, can fully be ensured, without interfering with the 2nd ring gear 14 adjacent to this 1st planetary gear 10. FIG. The web portion 10b, the short-axis boss portion 10a, the long-axis boss portion 13a, and the fifth ball bearing B5 are arranged such that their outer surfaces form a single plane.

  1, 2, and 3, a counterweight 15 is integrally connected to the input shaft 5 between the second ball bearing B <b> 2 and the first planetary gear 10. The counterweight 15 is arranged so that the phase of the center of gravity G2 around the main axis X1 is shifted from the phase of the eccentric axis X2 by 180 °.

  The counterweight 15 extends from the input shaft 5 in the radial direction to the arm portion 16, and from the tip portion of the arm portion 16 to the tooth portions where the first planetary gear 10 and the first ring gear 11 are not engaged with each other. And a weight portion 17 that protrudes. When the input shaft 5 is rotated, the counterweight 15 has a centrifugal force acting on the center of gravity G1 of the eccentric rotating body composed of the eccentric shaft 7 and the first and second planetary gears 10 and 13, and a centrifugal force acting on the center of gravity G2 of the counterweight 15. Its weight is set to balance the force. As a result, the rotational unbalance amount due to the eccentric rotating body can be made zero or significantly reduced.

  Further, by arranging the weight portion 17 of the counterweight 15 using the space between the tooth portions where the first and second planetary gears 10 and 13 are not meshed with each other, the rotational radius of the center of gravity G2 of the counterweight 15 is made as large as possible. , The centrifugal force acting on the center of gravity G2 can be increased, and the weight of the counterweight 15 can be reduced. At the same time, the displacement s along the main axis X1 between the centers of gravity G1 and G2 is reduced as much as possible. The couple of force exerted on the input shaft 5 by the centrifugal force acting on G2 can be kept small.

  The arm portion 16 of the counterweight 15 is bent so that the radially outer half portion 16b is offset toward the second ball bearing B2 with respect to the radially inner half portion 16a while making the thickness of each portion uniform. Due to this shape, a first recess 18 connected to the inner peripheral surface of the weight portion 17 is formed on one side surface of the arm portion 16 on the first planetary gear 10 side, and also on the second ball bearing B2 side. On the other side surface, second recesses 19 connected to the base of the arm portion 16 are formed. The first planetary gear 10 is disposed close to the counterweight 15 so that the protruding end portion of the rim portion 10c is accommodated in the first recess 18.

  At this time, the web portion 10b, the short-axis boss portion 10a, the long-axis boss portion 13a, and the outer surface aligned on one plane of the fifth ball bearing B5 have a small gap in the radially inner half 16a of the counterweight 15. It faces each other and does not hinder accommodation in the first recess 18 at one end of the rim portion 10c.

  Further, the counterweight 15 is disposed close to the second ball bearing B2 so that the second recess 19 accommodates the protruding inner end 3a of the first bearing boss 3 that supports the second ball bearing B2. .

  Thus, since the eccentric shaft 7 approaches the second ball bearing B2 while eliminating a useless space between the second ball bearing B2, the overhang amount of the eccentric shaft 7 from the second ball bearing B2 is increased. Can be reduced as much as possible. Therefore, when a bending load is applied to the eccentric shaft 7 by the meshing reaction forces of the first planetary gear 10 and the first ring gear 11, and the second planetary gear 13 and the second ring gear 14, the load on the second ball bearing B2 is reduced. Thus, the durability can be improved. Further, the reduction of the overhang amount of the eccentric shaft 7 contributes to the reduction of the size of the reduction gear R in the axial direction.

  Further, the arm portion 16 of the counterweight 15 is bent as described above, so that the thickness of each portion of the arm portion 16 is made equal, and the strength of the arm portion 16 is not reduced. The first and second recesses 18 and 19 can be easily provided.

  Next, the lubrication system in the planetary reduction gear R will be described.

  1 to 4, reference numeral F indicates a lubricating oil, and a predetermined amount of lubricating oil stored in the bottom of the gear case 1 in the lubricating oil F is indicated by Fa.

  The counterweight 15 has a weight portion 17 having the following structure in order to function as an oil diffusing member for diffusing the stored lubricating oil Fa when rotating. That is, the weight portion 17 has an arc shape in which the outer peripheral surface is close to the inner peripheral surface of the first ring gear 11, and a concave portion 21 is provided in the circumferential central portion of the inner peripheral surface. Further, on the inner periphery of the weight portion 17, a pair of concave curved surfaces 22 </ b> A that reach the recess 21 close to the outer peripheral surface of the first planetary gear 10 as it goes from the circumferential ends of the weight portion 17 toward the recess 21. 22B is provided. Further, both end portions in the circumferential direction of the weight portion 17 are formed in a tapered shape by the arc-shaped outer peripheral surface and the pair of concave curved surfaces 22A and 22B.

  On the other hand, the arm portion 16 of the counterweight 15 is provided with a through hole 23 that penetrates both side surfaces and opens at the bottom of the recess 21.

  The predetermined amount of the stored lubricating oil Fa at the bottom of the gear case 1 is such that when the leading end in the rotational direction A of the weight portion 17 reaches the lowest part, the leading end sinks into the stored lubricating oil Fa and When the planetary gear 10 reaches the top, the entire first planetary gear 10 is set to be exposed above the stored lubricating oil Fa.

  The description of the lubrication system continues. 1, 6 and 7, the first bearing boss 3 in the first case half 1 a of the gear case 1 is provided with an annular first oil sump chamber 25. The first oil sump chamber 25 is formed between the second ball bearing B2 and the first oil seal S1 so as to surround the entire circumference of the input shaft 5.

  Further, an oil receiving recess 26 is provided on the inner surface of the first case half 1a above the first bearing boss 3, and this oil receiving recess 26 is formed on the arm portion 16 when the counterweight 15 reaches the upper position. Arranged to face the outer surface. Further, the oil receiving recess 26 is formed in a fan shape whose width along the rotation direction of the counterweight 15 widens upward. The bottom of the oil receiving recess 26 is connected to the first oil sump chamber 25 via one or a plurality of descending passages 27.

  The first oil sump chamber 25 is opened to the bottom of the gear case 1 via one or a plurality of first overflow passages 28. The first overflow passage 28 allows excess lubricating oil to be removed from the gear case when the lubricating oil F accumulated in the first oil sump chamber 25 exceeds a predetermined amount sufficient to lubricate the second ball bearing B2 facing the first oil sump chamber 25. It is designed to return to 1.

  1, 6 and 7, the eccentric shaft 7 is provided with a hollow portion 30 which opens to the end surface thereof. Further, on one side wall of the eccentric shaft 7 facing the second ball bearing B2, the first oil hole 31 communicating between the second ball bearing B2 and the cavity 30 and the lubricating oil that has passed through the second ball bearing B2 are provided. A hook-shaped oil guide wall 32 that leads to the first oil hole 31 is provided. The oil guide wall 32 is formed in an arc shape close to the outer surface of the outer race of the second ball bearing B <b> 2 so that the inner peripheral surface thereof is continuous with the first oil hole 31. An oil block wall 33 that is bent inward in the radial direction and integrally connected to the outer peripheral surface of the input shaft 5 is connected to the rear end portion in the rotational direction A of the oil guide wall 32. The first oil hole 31 opens between the oil guide wall 32 and the oil block wall 33.

  The offset amount e of the eccentric shaft 7 with respect to the main axis X is larger than that in the illustrated example, and the first oil hole 31 is formed to have a larger diameter on the axial projection surface so as to overlap a part of the outer race of the second ball bearing B2. In this case, the oil guide wall 32 is preferably formed so as to be close to or surround the protruding inner end 3a of the first bearing boss 3 that supports the second ball bearing B2. .

  The oil guide wall 32 may be formed in an annular shape. In this case, the oil block wall 33 is unnecessary.

  Further, the circumferential wall of the eccentric shaft 7 has an annular groove 35 extending along the inner circumferential surface thereof, and the annular groove 35 communicates with intermediate portions of the fifth and sixth ball bearings B5 and B6 supported by the circumferential wall. Two oil holes 36 are provided. The second oil hole 36 is disposed at a position farthest from the main axis X1 on the peripheral wall of the eccentric shaft 7 or a position near the position. In other words, the second oil hole 36 is arranged in the direction farthest from the main axis X 1 on the peripheral wall of the eccentric shaft 7. A plurality of first and second oil holes 31 and 36 may be provided.

  1 and 4, the flange 6a of the output shaft 6 that fixes and supports the second ring gear 14 is provided with a plurality of lightening holes 37 facing the third ball bearing B3. The second bearing boss 4 of the gear case 1 is provided with an annular second oil sump chamber 40 that surrounds the output shaft 6 between the third ball bearing B3 and the second oil seal S2. The second oil sump chamber 40 is opened downward in the gear case 1 via the second overflow passage 41. The second overflow passage 41 allows the excess lubricating oil to be removed from the gear case when the lubricating oil F accumulated in the second oil sump chamber 40 exceeds a predetermined amount sufficient to lubricate the third ball bearing B3 facing the second oil sump chamber 40. It is designed to return to 1.

  The operation of this lubrication system will be described.

  When the counterweight 15 rotates downward as shown in FIG. 3 while the counterweight 15 is rotating, the weight portion 17 first sinks into the stored lubricating oil Fa at the bottom of the gear case 1 from its leading end, Then, the rotational direction is turned upward while scooping up the lubricating oil by one concave curved surface 22A following the leading end. By the way, the one concave curved surface 22A approaches the tooth portion of the first planetary gear 10 in accordance with the direction toward the concave portion 21 in the intermediate portion of the inner peripheral surface of the weight portion 17, so that the one concave curved surface 22A is ugly. Part of the raised lubricating oil is sprinkled on the teeth of the first planetary gear 10. In particular, since the rotation direction A of the counterweight 15 that rotates integrally with the input shaft 5 is opposite to the rotation direction of the first planetary gear 10, the one concave curved surface 22 </ b> A is connected to the tooth portion of the first planetary gear 10. While passing each other, the lubricating oil can be effectively sprinkled on the teeth. Therefore, the tooth part of the first planetary gear 10 sufficiently wetted with the lubricating oil meshes with the tooth part of the first ring gear 11, and the meshing part can be effectively lubricated.

  Further, another part of the lubricating oil scooped up by the one concave curved surface 22A is guided to the concave portion 21 in the middle portion of the inner peripheral surface of the weight portion 17, and the lubricating oil is accompanied by the rotation of the counterweight 15. By being swung around by the recesses 21 that are not present, they diffuse in a wide range in the gear case 1 and become splashes to lubricate each part in the gear case 1. Further, the lubricating oil that has flowed out from the side of the inner peripheral surface of the weight portion 17 is sprinkled particularly on the teeth of the second ring gear 14 and lubricates the meshing portion of the second reduction gear train 9.

  In this way, the weight portion 17 scoops up the stored lubricating oil Fa at the bottom of the gear case 1 by its rotation and diffuses it to the periphery, so that the outer peripheral surface of the weight portion 17 is a smooth arc surface concentric with the rotation center of the counterweight 15. When the first planetary gear 10 reaches the top, the entire first planetary gear 10 is exposed above the stored lubricating oil Fa. Therefore, the stirring resistance of the stored lubricating oil Fa by the weight portion 17 and the first planetary gear 10 is small, and power loss can be suppressed to a small value.

  Further, the second reduction gear train 9 is lubricated with diffusing lubricating oil, so that the amount of immersion of the rotating second ring gear 14 in the stored lubricating oil Fa at the bottom of the gear case 1 is minimized or zero. Therefore, the stirring resistance of the stored lubricating oil Fa by the teeth of the second ring gear 14 can be reduced or zero.

  Further, since the counterweight 15 also serves as an oil diffusing member for diffusing the stored lubricating oil Fa, a dedicated oil diffusing member is not required, and the structure can be simplified.

  Further, the weight portion 17 has a pair of concave curved surfaces 22A and 22B on the inner periphery that approach the tooth portion of the first planetary gear 10 and reach the concave portion 21 as it goes from the both end portions to the concave portion 21. Regardless of the rotational direction of 15, the stored lubricating oil Fa at the bottom of the gear case 1 can be scooped up by either one of the concave curved surfaces 22A, 22B, and the same effect as described above can be achieved.

  Further, another part of the lubricating oil scooped up by the weight portion 17 and guided to the recess portion 21 flows out and diffuses from the through hole 23 of the arm portion 16 toward the inner surface of the first case half 1a. The second ball bearing B2 is directly lubricated or received in the oil receiving recess 26 on the inner surface of the first case half 1a.

  The lubricating oil received in the oil receiving recess 26 flows down and accumulates in the first oil sump chamber 25 via the descending passage 27, passes through the bearing while lubricating the second ball bearing B2, and the first oil hole It moves to 31. During this time, the lubricating oil is hardly subjected to rotation from the input shaft 5, and therefore no back flow occurs due to centrifugal force. In addition, the lubricating oil that has passed through the second ball bearing B2 is guided by the oil guide wall 32 to the first oil hole 31 connected to the inner peripheral surface thereof, and further flows into the first oil hole 31 by the oil block wall 33. By being forced, it passes through the first oil hole 31 efficiently and flows into the cavity 30 of the eccentric shaft 7.

  When the annular oil guide wall 32 having no oil block wall 33 is employed, the lubricating oil that has passed through the second ball bearing B2 is efficiently transferred into the annular oil guide wall 32, and is annularly caused by centrifugal force. By being pressed against the inner peripheral surface of the oil guide wall 32, the oil guide wall 32 flows to the first oil hole 31 connected to the inner peripheral surface of the annular oil guide wall 32 and then to the cavity 30.

  The lubricating oil flowing into the cavity 30 in this manner is immediately captured in the annular groove 35 and receives a large centrifugal force due to the revolution of the eccentric shaft 7 around the main axis X1 so as to move away from the main axis X1. Flows out from the second oil hole 36 waiting at the farthest position from the main axis X1 or in the vicinity thereof to the fifth and sixth ball bearings B5 and B6, and lubricates these bearings.

  After the lubrication of the fifth and sixth ball bearings B5 and B6, the lubricating oil that has passed through these bearings becomes splashes to lubricate the first and second reduction gear trains 8 and 9, and the cavity 30 of the eccentric shaft 7 The lubricating oil that has flowed out of the opening is also splashed to lubricate the second reduction gear train 9.

  By the way, a predetermined amount or more of the lubricating oil accumulated in the first oil sump chamber 25 flows out from the first overflow passage 28 to the lower part of the gear case 1. As a result, a predetermined amount or more of lubricating oil necessary for lubricating the second ball bearing B2 is avoided from being accumulated in the first oil sump chamber 25, so that the operating resistance of the second ball bearing B2 due to the lubricating oil is kept small. Therefore, the circulation of the lubricating oil in the gear case 1 can be improved. In addition, even when the reduction gear R is stopped, a predetermined amount of lubricating oil can be continuously stored in the first oil sump chamber 25, so that the second ball bearing B2 and the like can be lubricated from the start of the reduction gear R operation. There is also.

  On the other hand, when the lubricating oil diffused by the counterweight 15 or the lubricating oil flowing out from the hollow portion 30 of the eccentric shaft 7 enters the second ring gear 14, a part of the lubricating oil is second reduced as described above. Although used for lubricating the meshing portion of the gear train 9, the remaining lubricating oil passes through the lightening hole 37 of the flange 6a of the output shaft 6, lubricates the third ball bearing B3, and passes through the bearing. In the second oil sump chamber 40.

  Also in the second oil sump chamber 40, a predetermined amount or more of the lubricating oil accumulated in the chamber flows out from the second overflow passage 41 to the lower portion of the gear case 1, thereby exceeding a predetermined amount necessary for the lubrication of the third ball bearing B3. It is possible to prevent the lubricating oil from accumulating. Therefore, the operating resistance of the third ball bearing B3 due to the lubricating oil can be suppressed to a small level, and the lubricating oil can be circulated well in the gear case 1. In addition, since a predetermined amount of lubricating oil can be continuously stored in the second oil reservoir 40, the third ball bearing B3 can be lubricated from the start of the operation of the reduction gear R.

  In the second embodiment of the present invention, as shown in FIG. 8, the inner peripheral surface of the weight portion 17 of the counterweight 15 is provided with a bowl-shaped concave portion 21 'deepening from both ends toward the center portion. A through hole 23 that penetrates the arm portion 16 opens in the deepest portion of the recess 21 ′. Other configurations are the same as those of the first embodiment, and in the figure, the same reference numerals are given to corresponding portions with the first embodiment, and the duplicated description is omitted.

  According to the second embodiment, when the counterweight 15 rotates, the weight portion 17 scoops up the stored lubricating oil Fa (see FIG. 3) at the bottom of the gear case 1 by the bowl-shaped concave portion 21, and the lubricating oil flows into the concave portion 21. Outflow to the side of the weight portion 17 as much as possible. As a result, most of the lubricating oil scooped up in the concave portion 21 flows out and diffuses from the through hole 23 of the arm portion 16 toward the inner side surface of the first case half 1a, so that it is directly applied to the second ball bearing B2. Lubrication and supply of lubricating oil to the oil receiving recess 26 can be effectively performed.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, in the above embodiment, the weight portion 17 of the counterweight 15 is formed to be bilaterally symmetric when viewed from the axial direction of the input shaft 5, but the center of gravity G2 of the counterweight 15 is opposite to the center of gravity G1 of the eccentric rotor. Of course, the phase may be asymmetrical. In this case, the concave portion 21 of the weight portion 17 is disposed behind the center portion of the inner peripheral surface of the weight portion 17 in the rotational direction of the weight portion 17, and the concave curved surface 22A is formed to be longer. The scooping distance with respect to the oil Fa can be increased, and the lubricating oil can be sprinkled more effectively on the teeth of the first planetary gear 10. In the planetary reduction gear R, various tooth forms such as a cycloid tooth shape or a circular tooth shape can be adopted for the planetary gear and the ring gear. If the output shaft 6 is changed to an input shaft and the input shaft 5 is changed to an output shaft, the reduction gear R can be changed to a speed increase gear.

  B2 ··· First bearing (second ball bearing); B5, B6 · · Second bearing (fifth and sixth ball bearing); F · · Lubricating oil; R · · Planetary transmission (planetary speed reducer) X1 ·· Main axis; X2 · Eccentric axis; 1 · Gear case; 5 · · First transmission shaft (input shaft), 6 · · Second transmission shaft (output shaft); 7 · · Eccentric shaft; · Motion conversion mechanism (second reduction gear train), ··· Planetary gear (first planetary gear); 11 · · Ring gear (first ring gear) · 15 · · Counterweight; 21 · · Recessed portion; 22A, 22B · · Concave surface, 23 ・ ・ Through hole

Claims (4)

A gear case, a first transmission shaft and a second transmission shaft that are rotatably supported via a first bearing and a second bearing that are axially spaced apart from each other in the gear case, and the first transmission shaft; An eccentric shaft that is coupled and rotates eccentrically around the axis of the first transmission shaft as the first transmission shaft rotates, a planetary gear that is rotatably supported by the eccentric shaft, and the first transmission to the gear case A ring gear fixed coaxially to a shaft and meshing with the planetary gear, a motion conversion mechanism for transmitting power between the planetary gear and the second transmission shaft, and an eccentric rotating body including the eccentric shaft and the planetary gear. A planetary transmission device comprising a counterweight coupled to the first transmission shaft to suppress rotational unbalance,
The counterweight has an arm portion extending in a radial direction from the first transmission shaft and a weight portion projecting to the side of the distal end portion of the arm portion, and a concave portion in an intermediate portion of the inner peripheral surface of the weight portion. Is provided,
A predetermined amount of lubricating oil is stored in the gear case, and when the leading end of the weight portion in the rotational direction reaches the lowest portion, the leading end sinks into the lubricating oil, and The planetary transmission device is set such that when the planetary gear reaches the uppermost position, the entire planetary gear is exposed above the lubricating oil. The planetary transmission device according to claim 1,
The weight portion is disposed between tooth portions of the planetary gear and the ring gear that are not meshed with each other, and has a concave curved surface that approaches the tooth portion of the planetary gear according to the direction from the leading end portion toward the concave portion. Planetary transmission device characterized by A planetary transmission device according to claim 2,
The concave portion is provided in a central portion of the inner peripheral surface of the weight portion, and the weight portion has a pair of concave curved surfaces that approach the tooth portion of the planetary gear according to the direction from the circumferential both ends toward the concave portion. Planetary transmission device characterized by The planetary transmission device according to any one of claims 1 to 3,
A planetary transmission device according to claim 1, wherein the arm portion is provided with a through hole that penetrates both side surfaces of the arm portion and communicates with the recess.

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